The burners of gas turbines comprise a plurality of tube-like fuel line systems which are embodied for different fuels. Each burner has a first end at which fuels can be supplied to the burner via different connecting ports. In the installed state the second end of the burner disposed opposite the first end of the burner leads into the combustion chamber of the gas turbine. The second end is usually provided with a plurality of nozzle systems from which the fuel or a fuel/air mixture can be injected into the combustion chamber. In order to securely mount the burner to a combustion chamber wall, a burner flange enclosing the burner is provided between the first and the second end and can be bolted to the combustion chamber wall.
During the operation of burners contamination can occur due to deposits, in particular in the region of the burner nozzles. Deposits can be caused for example as a result of the chemical reaction of sulfur compounds in the fuel with the base material of the burner components. As a result of said reaction, namely, iron sulfide deposits form in the interior of the burner. These sometimes lead to blocking of the holes through which the fuel is injected into the combustion chamber. This results in uneven combustion. As a consequence the burner can no longer deliver its full performance. In addition excessive deposits can damage burner components. In particular in the case of gas turbines a drop in power output due to contamination of the burner is detrimental, since this has a negative effect on the overall performance and the emission limit values of the gas turbine. The availability of the gas turbine is drastically compromised as a result.
Currently, when contaminants are detected in gas turbine burners, the burner nozzles are pierced by hand. Blow-out runs must then be carried out with the gas turbine during which any dirt residues will be blown out of the nozzles. Another method consists in installing new burners. This is associated with high costs, however. Since the problem occurs primarily on machines which are operated with preheat, there are likely to be a high number of machines requiring cleaning. Since different burners such as pilot or diffusion burners are present in an installation it is necessary to create a cleaning device which encompasses all burners. In addition it would be desirable to provide a cleaning device which can clean the burners in situ on the system without the necessity of dismantling the burner into its burner components.
U.S. Pat. No. 4,995,915 discloses a system for cleaning dirty gas firing nozzles in gas turbines, in which system a cleaning chemical is added to the gas while the gas turbine is in operation.
DE 10 2005 009 274 B3 relates to a cleaning method for combustor plants having at least one combustion chamber for post-combustion of combustion gases and in which at least one air jet is injected into the combustion chamber in order to improve the post-combustion by turbulences of the combustion gases. If necessary a swirl is imparted at times to the air jet of DE 10 2005 009 274 B3. Insofar as a swirl is already superimposed on the injected air jet for the purpose of improving the mixing process, the swirl for cleaning purposes is therefore generated in addition.